A known example of a super-resolution microscope is a fluorescence microscope that allows observation, at a high spatial resolution exceeding the diffraction limit, of a sample including molecules that have at least two or more excited quantum states (for example, see patent literature (PTL) 1 and 2).
With the molecules in the sample in a stable state, the fluorescence microscope disclosed in PTL 1 and PTL 2 spatially scans the sample surface with a fluorescence spot that is shrunk to the diffraction limit or lower, for example using a combination of pump light for excitation from a ground state to a first quantum state and erase light for causing molecules to transition further to another quantum state. A fluorescence image with resolution exceeding the spatial resolution at the diffraction limit is then obtained by two-dimensionally arranging the fluorescence signal at each measurement point and performing image processing on a computer.
As a representative example, the pump light is irradiated onto a sample including fluorophores, and the fluorophores are excited to a first quantum state. The molecules in the first quantum state are quenched by further irradiating the sample with the erase light to force the fluorophores to transition to another quantum state. As a result, fluorescence relaxation from the first quantum state is controlled. By the sample being simultaneously irradiated by pump light and a hollow erase light with an objective lens, the fluorescence spot formed on the sample surface that is dyed with fluorescent dye is shrunk to the diffraction limit or lower, leaving behind the central portion.